Intel Xeon E5640 's Advantages
Released 6 months late
Larger L3 cache size (12MB vs 8MB)
More modern manufacturing process (32nm vs 45nm)
Lower TDP (80W vs 95W)
Xeon X3450 's Advantages
Higher specification of memory (1333 vs 3)
Higher base frequency (2.667GHz vs 2.666GHz)